What appear to be the ruins of an early Christian church has been unearthed in Rome as electrical technicians were laying cables near the Tiber River.

As reported by Smithsonian.com, the remains of a luxurious building were found in the northern part of the city, 100 yards from the Ponte Milvio, a historic and important bridge from the era of the Roman Empire. The site consists of four rooms dating from the first and fourth centuries A.D., according to Italian news outlet La Repubblica.

Of the four rooms discovered at the dig site, some of the space appears to be a warehouse. Another one of the structures has walls made of brick and red, green, and honey-colored marble floors from Sparta, Egypt, and what is presently Tunisia, indicating that it was used for a special purpose, though the specifics remain unclear.

“It was definitely a building for public use and we think it may have been a place of worship,” said Marina Piranomonte, who directed the archaeological dig, in comments to the Telegraph. Others speculate that it was an ornate Roman villa.

Rome’s Archaeological Superintendency has called the discovery “an archaeological enigma shrouded in mystery.”

The Smithsonian noted that the Roman Empire’s earliest churches were constructed during Constantine’s reign in the fourth century.

“So while its significance is far from certain, the mysterious building may have been one of Rome’s early churches, built during a new era of tolerance for people of the Christian faith.”

The location of the ruins is garnering particular interest in that they were found so close to the historic bridge, which is also a site of the famous fourth century battle, known as The Battle of the Milvian Bridge, which Constantine won in October 312 A.D., a victory that paved the way for him to becoming the chief ruler of the Roman Empire and his acceptance of the Christian faith personally and making it the official religion of the land.